Abstract: The disclosure describes various techniques to control of small angle Mølmer-Sørensen (MS) gates and to handle asymmetric errors. A technique is described that implements a two-qubit calibration circuit with two MS gates, where a parameter ? represents an amount of entanglement of the MS gate. The calibration circuit is run for several values of ? to measure observed parity signals that are direct measurements of the values of ?. Calibration information is generated that describes the relationship between ? and the parity signals, and such calibration information is then provided to arbitrarily calibrate one or more MS gates in a quantum simulation. Another technique is described for using the calibration information in quantum simulations, including for quantum chemistry simulations.

Abstract: A method of performing a computation using a quantum computer includes generating a first laser pulse and a second laser pulse to cause entanglement interaction between a first trapped ion and a second trapped ion of a plurality of trapped ions that are aligned in a first direction, each of the plurality of trapped ions having two frequency- separated states defining a qubit, and applying the generated first laser pulse to the first trapped ion and the generated second laser pulse to the second trapped ion. Generating the first laser pulse and the second laser pulse includes stabilizing the entanglement interaction between the first and second trapped ions against fluctuations in frequencies of collective motional modes of the plurality of trapped ions in a second direction that is perpendicular to the first direction.

Abstract: Systems and techniques are provided for a camera server for heterogeneous cameras. A camera server may include a computing device that may a receive image data from a first camera and second image data from a second camera of a heterogenous system that may be a trapped ion quantum computer. The first camera may observe trapped ions. The second camera may observe optical systems and laser beams. The second image data may have a different format than the first image data. The computing device may convert the image data and the second image data into a format for a common data structure for image data, send the image data in the format for the common data structure for image data to client computing devices, and send the second image data in the format for the common data structure for image data to additional client computing devices.

Abstract: Embodiments described herein are generally related to a method and a system for performing a computation using a hybrid quantum-classical computing system, and, more specifically, to providing an approximate solution to an optimization problem using a hybrid quantum-classical computing system that includes a group of trapped ions. A hybrid quantum-classical computing system that is able to provide a solution to a combinatorial optimization problem may include a classical computer, a system controller, and a quantum processor. The methods and systems described herein include an efficient and noise resilient method for constructing trial states in the quantum processor in solving a problem in a hybrid quantum-classical computing system, which provides improvement over the conventional method for computation in a hybrid quantum-classical computing system.

Abstract: The disclosure describes the implementation of automated techniques for optimizing quantum circuits of the size and type expected in quantum computations that outperform classical computers. The disclosure shows how to handle continuous gate parameters and report a collection of fast algorithms capable of optimizing large-scale-scale quantum circuits. For the suite of benchmarks considered, the techniques described obtain substantial reductions in gate counts. In particular, the techniques in this disclosure provide better optimization in significantly less time than previous approaches, while making minimal structural changes so as to preserve the basic layout of the underlying quantum algorithms.

Abstract: Embodiments described herein are generally related to a method and a system for performing a computation using a hybrid quantum-classical computing system, and, more specifically, to providing an approximate solution to an optimization problem using a hybrid quantum-classical computing system that includes a group of trapped ions. A hybrid quantum-classical computing system that is able to provide a solution to a combinatorial optimization problem may include a classical computer, a system controller, and a quantum processor. The methods and systems described herein include an efficient and noise resilient method for constructing trial states in the quantum processor in solving a problem in a hybrid quantum-classical computing system, which provides improvement over the conventional method for computation in a hybrid quantum-classical computing system.

Abstract: Aspects of the present disclosure describe techniques for measuring collision rate with spatial filtering of scattered light. For example, a method for characterizing vacuum in a chamber is described that includes generating, inside the chamber, a potential well having a single, shallow potential region within which an ion is trapped, the shallow potential region having a lowest potential of the potential well, optically monitoring the ion within the potential well, detecting, based on the optically monitoring, a movement of the ion away from the shallow potential region in response to a collision with a background gas, and determining a pressure inside the chamber based on a rate of detected movements of the ion.

Abstract: Aspects of the present disclosure describe techniques for controlling quantum states of ions in an ion chain for a quantum operation. For example, a method is described that includes providing, from a first direction, a global optical beam to the ions in the ion chain, and providing, from a second direction different from the first direction, to each ion in a subset of the ions in the ion chain, a respective addressing optical beam. The method further includes dynamically controlling each of the addressing optical beams being provided by using a respective channel in a multi-channel acousto-optic modulator (AOM) to implement, with the ion chain, one or more quantum gates in a sequence of quantum gates of the quantum operation. Aspects of a quantum information processing (QIP) system that includes the multi-channel AOM for performing the method are also described.

Abstract: The disclosure describes various aspects of techniques for elliptical beam design using cylindrical optics that may be used in different applications, including in quantum information processing (QIP) systems. In an aspect, the disclosure describes an optical system having a first optical component having a first focal length, a second optical component having a second focal length and aligned with a first direction, and a third optical component having a third focal length and aligned with a second direction orthogonal to the first direction. The optical system is configured to receive one or more optical beams (e.g., circular or elliptical) and apply different magnifications in the first direction and the second direction to the one or more optical beams to image one or more elliptical Gaussian optical beams. A method for generating elliptical optical beams using a system as the one described above is also disclosed.

Abstract: A method of performing a computation using a quantum computer includes generating a first laser pulse and a second laser pulse to cause entanglement interaction between a first trapped ion and a second trapped ion of a plurality of trapped ions that are aligned in a first direction, each of the plurality of trapped ions having two frequency-separated states defining a qubit, and applying the generated first laser pulse to the first trapped ion and the generated second laser pulse to the second trapped ion. Generating the first laser pulse and the second laser pulse includes stabilizing the entanglement interaction between the first and second trapped ions against fluctuations in frequencies of collective motional modes of the plurality of trapped ions in a second direction that is perpendicular to the first direction.

Abstract: A method of performing simultaneous entangling gate operations in a trapped-ion quantum computer includes selecting a gate duration value and a detuning frequency of pulses to be individually applied to a plurality of participating ions in a chain of trapped ions to simultaneously entangle a plurality of pairs of ions among the plurality of participating ions by one or more predetermined values of entanglement interaction, determining amplitudes of the pulses, based on the selected gate duration value, the selected detuning frequency, and the frequencies of the motional modes of the chain of trapped ions, generating the pulses having the determined amplitudes, and applying the generated pulses to the plurality of participating ions for the selected gate duration value. Each of the trapped ions in the chain has two frequency-separated states defining a qubit, and motional modes of the chain of trapped ions each have a distinct frequency.

Abstract: Embodiments described herein are generally related to a method and a system for performing a computation using a hybrid quantum-classical computing system, and, more specifically, to providing an approximate solution to an optimization problem using a hybrid quantum-classical computing system that includes a group of trapped ions. A hybrid quantum-classical computing system that is able to provide a solution to a combinatorial optimization problem may include a classical computer, a system controller, and a quantum processor. The methods and systems described herein include an efficient and noise resilient method for constructing trial states in the quantum processor in solving a problem in a hybrid quantum-classical computing system, which provides improvement over the conventional method for computation in a hybrid quantum-classical computing system.

Abstract: A method of performing an entangling operation between two trapped ions in a quantum computer includes selecting a gate duration value of a pulse to be applied to a first ion and a second ion in a chain of trapped ions, determining one or more tones of the pulse, each tone comprising an amplitude value and a detuning frequency value, based on the selected gate duration value and frequencies of the motional modes of the chain of trapped ions, generating the pulse having the one or more tones, each tone comprising the determined amplitude and the determined detuning frequency values, and applying the generated pulse to the first and second ions for the gate duration value. Each of the trapped ions has two frequency-separated states defining a qubit, and motional modes of the chain of trapped ions each have a distinct frequency.

Abstract: The disclosure describes various aspects of a system with scalable and programmable coherent waveform generators. A network and digital-to-analog conversion (DAC) cards used by the network are described where each DAC card has a clock divider/replicator device with an input SYNC pin, a digital logic component, and one or more DAC components, and each output of the DAC components is used to control optical beams for a separate qubit of a quantum information processing (QIP) system. The network also includes a first distribution network to provide a clock signal to the clock divider/replicator device in the DAC cards, and a second distribution network to provide a start signal to the DAC cards, where the start signal is used by the digital logic component in the DAC card to assert the input SYNC pin when the start signal is asserted unless it is masked by the digital logic component.

Abstract: A method of performing a computation using a quantum computer includes generating a plurality of laser pulses used to be individually applied to each of a plurality of trapped ions that are aligned in a first direction, each of the trapped ions having two frequency-separated states defining a qubit, and applying the generated plurality of laser pulses to the plurality of trapped ions to perform simultaneous pair-wise entangling gate operations on the plurality of trapped ions. Generating the plurality of laser pulses includes adjusting an amplitude value and a detuning frequency value of each of the plurality of laser pulses based on values of pair-wise entanglement interaction in the plurality of trapped ions that is to be caused by the plurality of laser pulses.

Abstract: The disclosure describes aspects of laser cavity optical alignment, and more particularly, in situ alignment of optical devices in an optical system for replacement or upgrade. In one aspect, a method for optical alignment in an optical system is described that includes providing, via a positioning system, an optical beam to measure surface features and position of a first device under test (DUT), removing the first DUT from the optical system, placing a second DUT in the optical system at substantially the same position from which the first DUT was removed, providing, via the positioning system, an optical beam to measure surface features and position of the second DUT, aligning the second DUT based on the measurements made of the first DUT and the second DUT, and verifying operation of the second DUT in the optical system. The DUT can be an optical device such as an output optical coupler.

Abstract: Aspects of the present disclosure describe techniques for mitigating charging on optical windows. For example, a device for mitigating charges inside a chamber of a trapped ion system is described that includes an array of parallel wires formed from a single, conductive plate by cutting elongated gaps through an entire thickness of the conductive plate that separate the wires, an outer portion of the conductive plate to which the wires are attached is configured to position the wires to run parallel to one or more trapped ions in the chamber and to position the wires between a dielectric component of the chamber and the one or more trapped ions. A chamber with such an array of parallel wires and a method of using such an array of parallel wires are also described.

Abstract: The disclosure describes various aspects of quantum computer simulators. In an aspect, a method for characterizing a quantum computer simulator includes identifying simulator processes supported by the quantum computer simulator, generating, for each simulator process, characteristic curves for different gates or quantum operations, the characteristic curves including information for predicting the time it takes to simulate each of the gates or quantum operations in a respective simulator process, and providing the characteristic curves to select one of the simulator processes to simulate a circuit, quantum program, or quantum algorithm that uses at least some of the gates or quantum operations. In another aspect, a method for optimizing simulations in a quantum computer simulator is described where a simulator process is selected for simulation of a circuit, quantum program, or quantum algorithm based on characteristic curves that predict a time it takes for the simulation to be carried out.

Abstract: The disclosure describes various aspects of a practical implementation of multi-qubit gate architecture. A method is described that includes enabling ions in the ion trap having three energy levels, enabling a low-heating rate motional mode (e.g., zig-zag mode) at a ground state of motion with the ions in the ion trap; and performing a Cirac and Zoller (CZ) protocol using the low-heating rate motional mode as a motional state of the CZ protocol and one of the energy levels as an auxiliary state of the CZ protocol, where performing the CZ protocol includes implementing the multi-qubit gate. The method also includes performing one or more algorithms using the multi-qubit gate, including Grover's algorithm, Shor's factoring algorithm, quantum approximation optimization algorithm (QAOA), error correction algorithms, and quantum and Hamiltonian simulations. A corresponding system that supports the implementation of a multi-qubit gate architecture is also described.

Abstract: The disclosure describes various aspects of techniques for cooling a chain of ions to near the combined ground state that does not grow with the number of ions in the chain. By addressing each ion individually and using each ion to cool a different motional mode, it is possible to cool the motional modes concurrently. In an example, a third of the total motional modes can be cooled at the same time. In an aspect, the techniques include generating a sideband cooling laser beam for each ion in the ion chain, concurrently cooling two or more motional modes associated with the ions in the ion chain using the respective sideband cooling laser beam until each of the two or more motional modes reaches a motional ground state, and performing a quantum computation using the ion chain after the two or more motional modes have reached the motional ground state.